On its fifth birthday, Firefox must be considered both an incredible success and somewhat of a failure. The open source Web browser is a great product and quite an achievement, but has not tremendously advanced the cause of "free" software.
Indeed, Firefox has proven both open source supporters and skeptics to be correct: Yes, you can build an excellent, widely used open source application. No, it is not going to happen very often. (Brennon Slattery wrote a nice Firefox retrospective).
While Firefox is a formidable competitor, playing an important role in promoting Web standards, other open source desktop applications, such as OpenOffice, have failed to ignite much user interest.
You might think Firefox would have encouraged a wave of open source development, but from the perspective of a typical business or home user, it has not happened.
Firefox is the exception that proves the rule: There is no appetite for big open source development projects (that aren't operating systems).
For most users, the main attraction of open source software is price. "Good stuff for free" is a hard model to beat, but at some point developers have to earn a living. That is where Google comes in, bringing the successfully advertising subsidy model to nearly everything it touches.
Google has made huge fortunes and continues to pay nice salaries by giving useful things away. The company offers a mix of open source and proprietary software, but has a large revenue stream to support its development.
If there was ever going to be interest in new large-scale open source applications development, such as Firefox, Google has precluded it, though in a customer-friendly way.
To the extent that Firefox and what used to be a broad interest in open source was an antidote to Microsoft hegemony, Google has significantly taken care of that, too.
Firefox itself is a happy accident. Without the failure of Netscape, we might not have Firefox today. I will spare you the history and realize there will be different interpretations, but the Netscape dream lives on in Firefox.
I remember WWII movies where "war babies" were shipped off to grow up away from the conflict. That is how I think of Firefox--as the child Netscape shipped off to get away from the immediate war with Internet Explorer.
That Firefox subsequently became such a persistent thorn in Microsoft's side must bring some comfort to former Netscape partisans.
So, let me join the world in wishing Firefox a happy birthday (here is the official site for doing so). As one of an estimated 300,000 million daily users, I have benefited from the hard work that has gone into the project and thank those who made Firefox possible.
Sadly, the huge success of Firefox and the failure of the open source community to turn Firefox's success into something even larger proves open source is over as a major phenomenon in desktop applications. If it ever really was one.